Current draw characterizations of semiconductor power components (e.g., a semiconductor die) within electronic systems have always been difficult to determine. Such characterizations are however needed to appropriately design cooling and power solutions in the system design. By way of example, electronic systems often include thermal dissipation elements, such as heat sinks, to counter heat-generating components such as power supplies and microprocessors. To ensure proper thermal dissipation, the design of the system""s heat dissipation capacity is often made to over-compensate uncertainties in power consumption and dissipation relative to the heat-generating components. In one example, a power supply may be rated to a specified power dissipation; however this rating may not represent the actual performance of the supply in operation within the system. In another example, electronic system designers sometimes take temperature measurements of prototype devices and then perform calculations to predict future thermal loads within production systems; however, this technique also does not provide actual performance accuracy during operation because the power characterizations for individual components are not accurately known. Moreover, in this latter example, temperature measurements may be made for several components within the electronic system, causing cumulative errors in the thermal dissipation and power consumption estimates.
Accordingly, electronic systems are designed with certain thermal dissipation over-capacity to account for actual heat generation within the systems. Likewise, such systems are designed with certain power supply over-capacity to account for current draw and power variations for individual components of the systems. These over-capacities represent an increased cost of manufacture, such as the production cost for the heat sinks and power distribution components within the electronic system; in the world of highly competitive electronic computers and components, increased costs may make the underlying product uncompetitive.
The invention provides techniques and methods for improving estimation and measurement of transient and steady-state current draw for components within electronic systems. One feature of the invention is to provide methods for designing power and/or cooling solutions for electronic systems. Other features of the invention will be apparent within the description that follows.
The invention of one aspect is a method for characterizing current of power components within electronic systems. In one aspect, the method includes characterizing steady-state and/or transient current for the power components coupled with AC and/or DC power. In another aspect, the method includes characterizing current behavior for a single power component within an electronic system that connects to a ground and/or power plane; the system may also have a plurality of other power components connected to the ground and/or power plane.
Accordingly, one method of the invention provides the following steps. An electrical loop path is formed with a first printed circuit board to surround, at least in part, an electrical via of the first printed circuit board. The via connects to ground or a power plane. A power component operable with the first printed circuit board is connected to the via, to obtain power or to couple the component to ground. The power may be AC or DC power supplied to the power plane. The loop is coupled to an ammeter, or other current measurement device, to measure and/or characterize current during powered operation of the component. The current is used to specify cooling and/or power supply solutions for the electronic system utilizing the first printed circuit board and component.
In one aspect, the via connects to the ground plane of the first printed circuit board. In another aspect, the via connects to the power plane of the first printed circuit board. In another aspect, the loop is constructed and arranged as an internal track of the first printed circuit board. In still another aspect, the loop is formed with second printed circuit board that temporarily fits between the component and the first printed circuit board.
In another aspect, therefore, the method provides for determining power dissipation requirements for a heat sink used to dissipate heat from the component within the electronic system.
In another aspect, therefore, the method provides for determining power supply requirements for the component within the electronic system, the supply being capable of responding to step-load characterizations associated with the current draw of the component within the system.
In one aspect, the step of specifying power dissipation includes using via current (I) in a step of calculating power dissipation of the component as substantially equal to VI, V being the voltage potential between the ground and power planes.
In another aspect, a method is provided for determining current characterizations of power components in electronic system. A plurality of electrical loops are arranged to surround, at least in part, a plurality of vias of the system. In one aspect, one or more vias couple to ground of the electronic system. In another aspect, one or more vias couple to a power plane of the system. A plurality of power components operable with the system connect to ground and/or power through the vias. The loops are coupled to a measuring device to measure current and/or voltage of the power components during powered operation of the system. In one aspect, the currents from the power components are converted to estimated power dissipation of the system. In one aspect, the currents from the power components are converted to estimated transient current for the power components of the system. In still another aspect, the currents from the power components are converted to estimated steady-state current for the power components of the system.
In another aspect, the method provides for converting currents to an estimated power dissipation by calculating power for each of the components as substantially equal to VI, where V is the voltage between the ground and power planes and I is the current through the via. In still another aspect, the method includes the step of designing a heat sink to accommodate the estimated power dissipation.
In another aspect, the plurality of loops are constructed and arranged with the system as a statistical sampling of the vias. The method may further include the step of estimating (a) total power dissipation, (b) transient current draw, and/or (c) steady-state currents of all powered components in the system based on the statistical sampling.
In yet another aspect, the electrical system includes a first printed circuit board. The loops are constructed and arranged as tracks within the first printed circuit board. In yet another aspect, the loops are constructed and arranged within a second printed circuit board; the second circuit board is temporarily coupled between the power components and the first printed circuit board to estimate currents and/or power dissipation.
The invention of another aspect includes a test method for characterizing current of one or more power components of an electronic system. The power components connect to a printed circuit board via a plurality of pins; at least one of the pins for each of the components also connects to system power through one or more of the vias within the printed circuit board. An electrical loop is formed about one or more of the vias to characterize current associated therewith. The characterized current is used to assess current and/or power associated with the power components. In one aspect, transient current is determined from the characterized current. In another aspect, steady-state current is determined from the characterized current.
The invention is next described further in connection with preferred embodiments, and it will become apparent that various additions, subtractions, and modifications can be made by those skilled in the art without departing from the scope of the invention.